KR102502559B1 - Touch sensetive display device and driving device and method of the same - Google Patents

Abstract

The touch-sensitive display device of the present invention includes a plurality of pixels and a plurality of touch sensors, each touch sensor is connected to at least one or more pixels, is driven through a plurality of consecutive display frame periods, and each display frame a display panel to which image data of one frame in a period is applied to the pixels; and a touch driving device to apply touch driving signals to the touch sensors during one touch frame, wherein the one touch frame comprises: the display frame period It starts in a first display frame period among the display frame periods and ends in a second display frame period immediately following the first display frame period among the display frame periods.

Description

Touch-sensitive display device and its driving circuit and method

The present invention relates to a touch-sensing display device capable of touch sensing, and a driving circuit and method therefor.

A user interface (UI) allows a person (user) to easily control various electronic devices as he/she wants. Representative examples of such a user interface include a keypad, a keyboard, a mouse, an on-screen display (OSD), a remote controller having an infrared communication function or a radio frequency (RF) communication function, and the like. User interface technology continues to evolve in the direction of enhancing user sensibility and convenience of operation. Recently, user interfaces are evolving into touch UIs, voice recognition UIs, 3D UIs, and the like.

Touch UI is essential for portable information devices. The touch UI is implemented as a method of forming a touch screen on a screen of a display device. Such a touch screen may be implemented in a capacitive manner. A touch screen having a capacitive touch sensor senses a change in capacitance according to the input of a touch driving signal, that is, a change in charge of the touch sensor, when a finger or a conductive material contacts (or approaches) the touch sensor. detect touch input

In order to increase a touch feeling felt by a user on a capacitive touch screen, a touch report rate should be increased. This is because the host system updates the coordinates of the touch input at the frequency of the touch reporter rate. Accordingly, the response speed of the host system to touch input is proportional to the touch reporter rate.

In the in-cell touch sensor technology in which touch sensors of a touch screen are embedded in a pixel array of a display panel, it is difficult to improve a touch reporter rate because a display period and a touch period are time-divided within one display frame period. In general, in the in-cell touch technology, the touch reporter rate is set equal to the display frame rate. Here, the touch reporter rate means a frequency at which coordinate data obtained by sensing all touch sensors in the touch screen are transmitted to an external host system. The display frame rate means a frequency at which new data is updated in all pixels in the display panel. The higher the touch reporter rate, the faster the coordinates of the touch input are updated, so that the touch sensitivity felt by the user can be increased and the trace of the touch input can be expressed in detail. However, since the prior art recognizes a touch input at a touch reporter rate equal to the display frame rate, it is difficult to implement a high-speed response to the touch input. If the response to the touch input is slow, in the case of fast-moving line drawing, the distance between coordinate points that are continuously recognized increases, and the line may be recognized as a line of a different form from the curved expression drawn by the user.

In order to increase the touch reporter rate in the in-cell touch sensor technology, a method of allocating a plurality of touch frames TF1 and TF2 within one display frame period has been proposed as shown in FIG. 1 . In FIG. 1 , M01 to M14 denote multiplexers that sequentially sense touch blocks (one touch block includes a plurality of touch sensors) of the touch screen. Each of the touch frames TF1 and TF2 includes a plurality of touch sections corresponding to the multiplexers M01 to M14 one by one. Here, 1 touch frame indicates a period in which the touch reporter is output. The multiplexers M01 to M14 are sequentially switched on during touch periods synchronized with the first logic level of the touch enable signal TEN. Then, the sensing unit sequentially senses the capacitance change of the touch sensors in a block unit through the multiplexers M01 to M14. Since the sensing operation of the multiplexers M01 to M14 is performed once for each touch block during one touch frame, when two touch frames TF1 and TF2 are allocated within one display frame period as shown in FIG. The sensing operation of the multiplexers M01 to M14 targeting each touch block is performed twice.

However, in the conventional in-cell touch sensor technology, a surplus period (TD) not utilized as a touch period occurs within one display frame period. Since the surplus period (TD) is shorter than one touch frame, it is not used as a touch period. The reason for the TD is that the conventional touch reporter rate is implemented as an integer multiple of the display frame rate.

The surplus period (TD) inevitably occurs in every display frame period. As a result, the conventional in-cell touch sensor technology has limitations in increasing the touch reporter rate due to the excess period (TD).

Accordingly, an object of the present invention is to provide a touch-sensitive display device, a driving circuit and a method thereof capable of eliminating an excessive period not utilized as a touch period within one display frame period and improving a touch reporter rate.

In order to achieve the above object, the touch-sensitive display device of the present invention includes a plurality of pixels and a plurality of touch sensors, each touch sensor is connected to at least one pixel, and a plurality of consecutive display frame periods. a display panel driven through a display panel and applying image data of one frame to the pixels in each display frame period; and a touch driving device for applying touch driving signals to the touch sensors during one touch frame, wherein the one touch A frame starts in a first display frame period of the display frame periods and ends in a second display frame period immediately following the first display frame period of the display frame periods.

The present invention increases the touch reporter rate by a non-integer multiple (N.M times, N and M are positive integers) compared to the display frame rate, thereby eliminating the surplus period that is not utilized as a touch period within one display frame period and increasing the touch reporter rate. can be further improved.

Furthermore, the present invention further allocates a dummy touch section for distinguishing touch frames within one display frame period and utilizes the dummy touch section for communication with an active stylus pen, thereby effectively providing not only a touch input position but also pen additional functions. can detect

1 is a diagram showing a surplus period not used as a touch period in one display frame period in a conventional in-cell touch sensor technology;
2 is a view showing a touch-sensitive display device according to an embodiment of the present invention.
3 is a diagram showing an example of a touch sensor embedded in a pixel array;
FIG. 4 is a timing diagram illustrating a method of time-division driving the pixels and touch sensors of the display panel shown in FIG. 3;
5 to 7 are views showing a touch driving device according to an embodiment of the present invention.
8 is a diagram showing multiplexers and sensing units connected to touch sensor blocks;
9 is a diagram showing one method for increasing the touch reporter rate according to the present invention.
10 and 11 are diagrams showing that the time taken from the start of a display frame to the first touch reporter is different in neighboring display frames according to the present invention.
12 is a diagram showing another method for increasing the touch reporter rate according to the present invention.
13 and 14 show another method for increasing the touch reporter rate according to the present invention.
15 to 18 are diagrams showing an example of implementing a frequency hopping technique using the dummy touch section included in FIGS. 13 and 14;
19 is a diagram showing an example of a touch driving signal for communication with an active stylus pen.
20 is a diagram showing an example of sensing pen information based on a pen driving signal input from an active stylus pen.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Like reference numbers throughout the specification indicate substantially the same elements. In the following description, if it is determined that a detailed description of a known function or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

2 shows a touch-sensitive display device including a touch driving device according to an embodiment of the present invention. 3 shows an example of a touch sensor embedded in a pixel array. FIG. 4 shows a method of time-division driving the pixels and touch sensors of the display panel shown in FIG. 3 . 5 to 7 show a touch driving device according to an embodiment of the present invention. 8 shows multiplexers and sensing units connected to touch sensor blocks.

2 to 8, the touch-sensitive display device 10 of the present invention includes a liquid crystal display (LCD), a field emission display (FED), and a plasma display panel (Plasma Display). Panel, PDP), Organic Light Emitting Display (OLED), Electrophoresis (EPD), and the like can be implemented based on flat panel display devices. In the following embodiments, the touch-sensitive display device is implemented as a liquid crystal display device, but the touch-sensitive display device of the present invention is not limited to the liquid crystal display device.

The touch-sensitive display device 10 includes a display module and a touch module.

The touch module includes a touch screen (TSP) and a touch driving device 18 .

The touch screen TSP may be implemented in a capacitive manner that senses a touch input through a plurality of capacitive sensors. The touch screen TSP includes a plurality of touch sensors having capacitance. Capacitance can be divided into self capacitance and mutual capacitance. Self-capacitance may be formed along a single-layer conductor line formed in one direction, and mutual capacitance may be formed between two orthogonal conductor lines.

Touch sensors of the touch screen TSP may be embedded in a pixel array of the display panel DIS. An example in which the touch screen TSP is embedded in the pixel array of the display panel DIS is shown in FIG. 3 . Referring to FIG. 3 , the pixel array of the display panel DIS includes touch sensors C1 to C4 and sensor lines L1 to Li, where i is smaller than m and n and connected to the touch sensors C1 to C4. positive integers). The common electrode COM of the pixels 101 is divided into a plurality of segments. The touch sensors C1 to C4 are implemented with divided common electrodes COM. One common electrode segment is commonly connected to a plurality of pixels 101 and forms one touch sensor. Therefore, as shown in FIG. 4 , the touch sensors C1 to C4 supply the common voltage Vcom to the pixels 101 during the display period Td1 and Td2 for writing image data, and the touch period Tt1 and Tt2 ), it receives the touch driving signal Tx and senses the touch input. 3 shows a self-capacitance type touch sensor, the touch sensors C1 to C4 are not limited thereto.

The touch driving device 18 applies the touch driving signal Tx to the touch sensors C1 to C4 and senses the amount of change in charge of the touch sensors C1 to C4 so as to be conductive like a finger (or stylus pen). Determine whether or not a material has been touched and its location.

The touch driving device 18 drives the touch sensors during the touch periods Tt1 and Tt2 in response to the touch enable signal TEN input from the timing controller 16 or the host system 19 . The touch driving device 18 senses a touch input by supplying the touch driving signal Tx to the touch sensors C1 to C4 through the sensor lines L1 to Li during the touch periods Tt1 and Tt2. The touch driving device 18 determines touch input by analyzing the change in charge of the touch sensor, which varies depending on whether or not there is a touch input, and calculates the coordinates of the touch input position. The coordinate information of the touch input position is transmitted to the host system in the form of a touch reporter. The touch reporter rate is the rate at which touch reporters are transmitted to the host system.

The touch driving device 18 drives the touch sensors C1 to C4 in response to the touch enable signal TEN during the touch periods Tt1 and Tt2, and the touch sensors display the input image within one display frame period. By allocating at least two or more touch frames for driving (C1 to C4), the touch report rate is higher than the display frame rate. Here, a plurality of touch periods corresponding to the number of multiplexers may be included in one touch frame.

For example, if the display period (Td1, Td2) and the touch period (Tt1, Tt2) are divided into a plurality of periods as shown in FIG. , Tt2), the touch input is sensed, and coordinate information of the touch input is transmitted to the host system when each touch frame is completed. Accordingly, the present invention can increase the touch report rate more than the display frame rate. The display frame rate is the frame frequency at which one frame image is written to the pixel array. The touch reporter rate is the rate at which coordinate information of a touch input is generated. The higher the touch reporter rate, the faster the coordinate recognition speed of the touch input, so the touch sensitivity improves.

In particular, the touch driver 18 can further improve the touch reporter rate by eliminating the surplus period not utilized as a touch period within one display frame period and utilizing one display frame period as a touch frame.

The touch driving device 18 of the present invention may be implemented as an integrated circuit (IC) package as shown in FIGS. 5 to 7 .

Referring to FIG. 5 , the touch driving device 18 includes a driver IC (DIC) and a touch IC (TIC).

The driver IC (DIC) includes a touch sensor channel unit 100, a Vcom buffer 110, a switch array 120, a timing control signal generator 130, a multiplexer (MUX) 140, and a DTX compensator ( 150).

The touch sensor channel unit 100 is connected to the electrodes of the touch sensors through sensor lines and connected to the Vcom buffer 110 and the multiplexer 140 through the switch array 120 . A multiplexer 140 connects the sensor lines to a touch IC (TIC). In the case of the 1:3 multiplexer, the multiplexer 140 reduces the number of channels of the touch IC (TIC) by sequentially connecting one channel of the touch IC (TIC) to three sensor lines in a time division manner. The multiplexer 140 sequentially selects sensor lines to be connected to channels of the touch IC (TIC) in response to MUX control signals (MUX C1 to C3). The multiplexer 140 is connected to channels of the touch IC (TIC) through touch lines.

The Vcom buffer 110 outputs a common voltage Vcom of pixels. The switch array 120 supplies the common voltage Vcom from the Vcom buffer 110 to the touch sensor channel unit 100 during the display period under the control of the timing control signal generator 130 . The switch array 120 connects the sensor lines to the touch IC (TIC) during the touch period under the control of the timing control signal generator 130 .

The timing control signal generation unit 130 generates timing control signals for controlling operation timings of a display driving circuit and a touch IC (TIC).

The timing control signal generator 130 may be included in the timing controller 16 shown in FIG. 2 . The timing control signal generator 130 drives the display driving circuit during the display period and drives the touch IC (TIC) during the touch period.

As shown in FIG. 4 , the timing control signal generation unit 130 generates the touch enable signal TEN defining the display period Td1 and Td2 and the touch period Tt1 and Tt2 to form a display driving circuit and a touch IC (TIC). synchronize The display driving circuit writes image data to pixels during the first level period of the touch enable signal TEN. The touch IC (TIC) senses a touch input by driving touch sensors in response to the second level of the touch enable signal (TEN). The first level of the touch enable signal TEN may be a high level, and the second level may be a low level, but may be set to the opposite.

The touch IC (TIC) is connected to a driving power supply unit (not shown) to receive driving power. The touch IC (TIC) generates a touch driving signal Tx in response to the second level of the touch enable signal TEN and applies it to the touch sensors. The touch driving signal Tx may be generated in various forms such as a square wave pulse, a sine wave, a triangular wave, etc., but is preferably implemented as a square wave. The touch driving signal Tx may be applied N times to each of the touch sensors so that charges may be accumulated N times (where N is a natural number equal to or greater than 2) or more in the integrator of the touch IC TIC.

Noise may increase in a touch sensor signal according to a change in input image data. The DTX compensator 150 analyzes the input image data, removes noise components from the touch raw data according to the gray level change of the input image, and transmits the noise component to the touch IC (TIC). DTX stands for Display and Touch crosstalk. Content related to the DTX compensator 150 is described in detail in Patent Application No. 10-2012-0149028 (application filed on December 19, 2012) filed by the present applicant. In the case of a system in which the noise of the touch sensor does not change sensitively according to the data change of the input image, the DTX compensator 150 is unnecessary and can be omitted. In FIG. 5, DTX DATA is output data of the DTX compensator 150.

The touch IC (TIC) drives the multiplexer 140 during the touch intervals Tt1 and Tt2 in response to the touch enable signal TEN from the timing control signal generator 130 to pass through the multiplexer 140 and the sensor lines. Receives the charge of the touch sensor. In FIG. 5, MUXs C1 to C3 are signals for selecting channels of a multiplexer.

The touch IC (TIC) detects the amount of change in charge before and after the touch input from the touch sensor signal, compares the amount of change in charge with a predetermined threshold value, and determines the locations of touch sensors having a change in charge equal to or greater than the threshold value as the touch input area. The touch IC (TIC) calculates coordinates for each touch input and transmits touch data (TDATA(XY)) including touch input coordinate information to the external host system 19 . A touch IC (TIC) includes an amplifier that amplifies the charge of the touch sensor, an integrator that accumulates the charge received from the touch sensor, an analog to digital converter (ADC) that converts the voltage of the integrator into digital data, and an operation logic unit. The operation logic unit compares the touch raw data output from the ADC with a threshold value, determines a touch input according to the comparison result, and executes a touch recognition algorithm that calculates coordinates.

A driver IC (DIC) and a touch IC (TIC) may transmit and receive signals through a Serial Peripheral Interface (SPI) interface.

The host system 19 refers to a system body of an electronic device to which the touch-sensitive display device 10 of the present invention is applicable. The host system 19 may be any one of a phone system, a television (TV) system, a set-top box, a navigation system, a DVD player, a Blu-ray player, a personal computer (PC), and a home theater system. The host system 19 transmits input image data (RGB) to the driver IC (DIC), receives touch input data (TDATA(XY)) from the touch IC (TIC), and generates an application associated with the touch input. run

Referring to FIG. 6 , the touch driving device 18 includes a driver IC (DIC) and a Micro Controller Unit (MCU).

The driver IC (DIC) includes a touch sensor channel unit 100, a Vcom buffer 110, a switch array 120, a first timing control signal generator 130, a multiplexer 140, a DTX compensator 150, a sensing It includes a unit 160, a second timing control signal generator 170 and a memory 180. This embodiment differs from the above-described embodiment of FIG. 5 in that the sensing unit 160 and the second timing control generator 170 are integrated into a driver IC (DIC). The first timing control generator 130 is substantially the same as that of FIG. 5 . Accordingly, the first timing control generator 130 generates timing control signals for controlling operation timings of the display driving circuit and the touch IC (TIC).

The multiplexer 140 floats the touch sensor electrodes accessed by the sensing unit 160 under the control of the MCU. The sensing unit 160 accesses touch sensor electrodes other than touch sensor electrodes connected to pixels that charge the data voltage. The multiplexer 140 may supply a common voltage Vcom under the control of an MCU. When the resolution of the touch screen is M×N as shown in FIG. 8 (M and N are each a positive integer greater than or equal to 2), the number of multiplexers 140 required is M. When the resolution of the touch screen is M×N, the touch sensor electrodes 22 are divided into M×N numbers. Each multiplexer 140 is connected to N touch sensor electrodes 22 through N sensor lines 115, and sequentially connects N sensor lines 115 to one sensing unit 160. .

The sensing unit 160 is connected to the sensor lines 115 through the multiplexer 140 to measure changes in voltage waveforms received from the touch sensor electrodes 22 and converts them into digital data. The sensing unit 160 includes an amplifier that amplifies the received voltage of the touch sensor electrodes 22, an integrator that accumulates the voltage of the amplifier, and an analog-to-digital converter that converts the voltage of the integrator into digital data. , hereinafter referred to as "ADC"). The digital data output from the ADC is transmitted to the MCU as touch raw data. When the resolution of the touch screen is M×N as shown in FIG. 8 (M and N are each a positive integer greater than or equal to 2), M sensing units 160 are required.

The second timing control generating unit 170 generates timing control signals, clocks, and the like for controlling operation timings of the multiplexer 140 and the sensing unit 160 . The DTX compensator 150 in the driver IC (DIC) may be omitted. The memory 180 temporarily stores the touch raw data TDATA under the control of the second timing control generator 170 .

A driver IC (DIC) and an MCU can transmit and receive signals through a Serial Peripheral Interface (SPI) interface. The MCU compares the touch raw data (TDATA) with a threshold value, determines a touch input according to the comparison result, and executes a touch recognition algorithm that calculates coordinates.

Referring to FIG. 7 , the touch driving device 18 includes a driver IC (DIC) and a memory (Memory, MEM).

The driver IC (DIC) includes a touch sensor channel unit 100, a Vcom buffer 110, a switch array 120, a first timing control signal generator 130, a multiplexer 140, a DTX compensator 150, a sensing It includes a unit 160, a second timing control signal generator 170, a memory 180, and an MCU 190. This embodiment differs from the above-described embodiment of FIG. 6 in that the MCU 190 is integrated into a driver IC (DIC). The MCU 18 compares the touch raw data TDATA with a threshold value, determines a touch input according to the comparison result, and executes a touch recognition algorithm that calculates coordinates.

The memory MEM stores register setting values related to timing information necessary for the operation of the display driving circuit and the sensing unit 160 . When the power of the touch-sensitive display device is turned on, the register setting values are loaded from the memory MEM to the first timing control signal generator 16 and the second timing control signal generator 170 . The first timing control signal generation unit 16 and the second timing control signal generation unit 170 generate timing control signals for controlling the display driving circuit and the sensing unit 160 based on the register setting values read from the memory. do. It is possible to respond to model change by changing register setting values of the memory MEM without structural change of the driving device.

The display module may include a display panel (DIS), display driving circuits 12, 14, and 16, and a host system 19.

The display panel DIS includes a liquid crystal layer formed between two sheets of substrates. The pixel array of the display panel DIS includes pixels formed in a pixel area defined by data lines (D1 to Dm, where m is a positive integer) and gate lines (G1 to Gn, where n is a positive integer). . Each of the pixels is connected to TFTs (Thin Film Transistors) formed at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn, a pixel electrode that charges the data voltage, and a pixel electrode to form a liquid crystal cell. A storage capacitor (Cst) for maintaining a voltage may be included.

A black matrix, a color filter, and the like may be formed on the upper substrate of the display panel DIS. A lower substrate of the display panel DIS may be implemented as a color filter on TFT (COT) structure. In this case, the black matrix and color filters may be formed on the lower substrate of the display panel DIS. The common electrode to which the common voltage is supplied may be formed on an upper substrate or a lower substrate of the display panel DIS. A polarizing plate is attached to each of the upper and lower substrates of the display panel DIS, and an alignment layer for setting a pretilt angle of the liquid crystal is formed on an inner surface in contact with the liquid crystal. A column spacer for maintaining a cell gap of the liquid crystal cell is formed between the upper substrate and the lower substrate of the display panel DIS.

A backlight unit may be disposed under the rear surface of the display panel DIS. The backlight unit is implemented as an edge type or direct type backlight unit and irradiates light to the display panel DIS. The display panel DIS may be implemented in any known liquid crystal mode, such as a twisted nematic (TN) mode, a vertical alignment (VA) mode, an in plane switching (IPS) mode, and a fringe field switching (FFS) mode.

The display driving circuit includes a data driving circuit 12, a gate driving circuit 14, and a timing controller 16 to write video data of an input image to pixels of the display panel DIS. The data driving circuit 12 converts the digital video data (RGB) input from the timing controller 16 into an analog positive/negative polarity gamma compensation voltage and outputs a data voltage. The data voltage output from the data driving circuit 12 is supplied to the data lines D1 to Dm. The gate driving circuit 14 sequentially supplies a gate pulse (or scan pulse) synchronized with the data voltage to the gate lines G1 to Gn to select a pixel line of the display panel DIS to which the data voltage is written.

The timing controller 16 inputs timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), a data enable signal (Data Enable, DE), and a main clock (MCLK) input from the host system 19. and the operation timings of the data driving circuit 12 and the gate driving circuit 14 are synchronized. The scan timing control signal includes a gate start pulse (GSP), a gate shift clock, a gate output enable signal (GOE), and the like. The data timing control signal includes a source sampling clock (SSC), a polarity control signal (Polarity, POL), a source output enable signal (Source Output Enable, SOE), and the like.

The host system 19 transmits timing signals (Vsync, Hsync, DE, MCLK) together with digital video data (RGB) to the timing controller 16, and touch coordinate information (XY) input from the touch driver 18. ) and associated applications can be executed.

Meanwhile, the touch enable signal TEN of FIG. 4 may be generated by the host system 19 . During the display period Td1 and Td2, the data driving circuit 12 supplies data voltages to the data lines D1 to Dm under the control of the timing controller 16, and the gate driving circuit 14 controls the timing controller 16. ), gate pulses synchronized with the data voltage are sequentially supplied to the gate lines G1 to Gn. Meanwhile, during the display periods Td1 and Td2, the touch driving device 18 stops operating.

During the touch periods Tt1 and Tt2, the touch driving device 18 applies the touch driving signal Tx to the touch sensors of the touch screen TSP. Meanwhile, during the touch periods Tt1 and Tt2, the display driving circuits 12, 14, and 16 minimize parasitic capacitance between the signal lines D1 to Dm and G1 to Gn connected to the pixels and the touch sensors. AC signals having the same amplitude and phase as the touch driving signal Tx may be supplied to the signal lines D1 to Dm and G1 to Gn. In this case, the display noise mixed with the touch sensing signal is drastically reduced and the accuracy of the touch sensing is increased.

Meanwhile, the touch-sensitive display device 10 of the present invention may further include an active stylus pen 20 communicating with the touch driving device 18 . The active stylus pen 20 generates a pen drive signal based on the touch drive signal Tx input from the touch screen TSP and outputs the pen drive signal to a contact point with the touch screen TSP, so that the touch drive device 18 It helps to find the touch input location on the touch screen (TSP). In particular, the touch driving device 18 of the present invention informs the active stylus pen 20 of a dummy touch period for classifying touch frames, and pen information (pen pen pressure, pen ID, etc.) can be effectively detected. This will be described later with reference to FIGS. 19 and 20 .

9 shows a method for increasing the touch reporter rate according to the present invention. 10 and 11 show that the time taken from the start of the display frame to the first touch reporter is different in neighboring display frames according to the present invention. And, FIG. 12 shows another method for increasing the touch reporter rate according to the present invention.

9 to 11, the touch driving device 18 according to the present invention includes at least two touch frames (parts of TF1, TF2, and TF3) for driving touch sensors within one display frame period displaying an input image. By over-allocating, the touch report rate is higher than the display frame rate. One display frame period may be defined as a period between rising edges of adjacent vertical sync signals Vsync. During the display frame period, the data driving circuit 12 writes new image data to all pixels of the display panel through the data lines. The display frame period is normally inversely proportional to the display frame rate of the display device 10 . For example, when the display frame rate is 60 Hz, the display frame period becomes 1/60 second. Here, 1 touch frame indicates a period in which the touch reporter is output. That is, one touch frame indicates a touch cycle required for the touch driving device 18 to sense all the touch sensor electrodes 22 once by driving all the touch sensor lines 115 . One touch reporter is output for each touch period. One touch frame may include multiple touch periods. Each touch period is performed when the touch enable signal TEN has a low logic level. During one touch period, touch driving signals are supplied to some of the touch sensor electrodes 22, and touches for some of the touch sensor electrodes 22 are sensed. Therefore, a plurality of touch intervals are required to drive and sense all the touch sensor electrodes 22 .

In an embodiment of the present invention, a case of driving a touch screen having a resolution of 14×N using 14 multiplexers M01 to M14 will be described as an example. Therefore, in the present invention, one touch frame is the time required for all 14 multiplexers M01 to M14 to operate in order to drive all touch sensor lines 115 of the display panel. The multiplexers M01 to M14 sequentially connect the touch blocks of the touch screen (one touch block includes a plurality of touch sensors arranged in one column) to the sensing unit. The multiplexers M01 to M14 are sequentially switched on during touch periods synchronized with the second logic level (low logic level) of the touch enable signal TEN. Then, the sensing unit sequentially senses the capacitance change of the touch sensors in a block unit through the multiplexers M01 to M14. The number of multiplexers M01 to M14 may be the same as the number of touch blocks.

Unlike this, in another embodiment, the touch screen may have a resolution of M × 14. Here, M is a multiplexer connected to each of the 14 touch sensor lines 115 . In this embodiment, M01 to M14 represent touch intervals in which the 14 touch sensor lines 115 connected to the multiplexers are selected by the multiplexers. For example, during the touch period M01, each multiplexer selects the sensor line 115 connected to the touch sensor electrodes 22 of the first row in FIG. During the touch period M02, each multiplexer selects the sensor line 115 connected to the touch sensor electrodes 22 of the second row in FIG. Therefore, in each touch period, the different touch sensor lines 115 and the touch sensor electrodes 22 connected thereto are driven by the touch driving signal.

Meanwhile, the display driving circuit writes image data to pixels in display sections. Also, the display driving circuit applies a common voltage to the touch sensor electrodes 22 in display sections. The display periods are synchronized with the touch enable signal TEN, and are formed when the touch enable signal TEN has a high logic level. As shown in FIG. 9 , as the touch enable signal TEN is toggled, the touch period and the display period are alternated.

The touch driver 18 according to the present invention increases the touch reporter rate by a non-integer multiple (N.M times, N and M are positive integers) compared to the display frame rate, so that within one display frame period, it is not utilized as a touch period. The redundant period can be eliminated and the touch reporter rate can be further improved. The touch driving device 18 of the present invention allocates to the first and second touch frames TF1 and TF2 within one display frame period and does not leave the remaining period as an surplus period, and part of the third touch frame TF3 Eliminate surplus periods by using them as periods.

The touch driving device 18 according to the present invention assigns a touch frame to the entire section of one display frame period, so that the period from the start of the display frame to the first touch reporter in at least two adjacent display frame periods make them different from each other.

Moreover, when there are immediately consecutive first display frame and second display frame, some touch frames start the touch frame in the first display frame period and complete the touch frame in the second display frame period. For this divided touch frame, some touch sensor electrodes 22 are driven and sensed by touch driving signals during the first display frame, and the remaining touch sensor electrodes 22 excluding the some touch sensor electrodes 22 ) is driven and sensed by the touch driving signals during the second display frame. A one-time touch reporter including touch coordinates is a result obtained according to touch driving signals applied during divided touch frames.

For example, Fig. 10 shows three consecutive display frame periods (Fn-1, Fn, Fn+1). The display frame period Fn immediately follows the display frame period Fn-1, and the display frame period Fn+1 immediately follows the display frame period Fn. As shown in FIG. 10 , when the first to seventh touch frames TF1 to TF7 are allocated to the n-1th, nth, and n+1th display frame periods Fn-1, Fn, and Fn+1, The first period TI1 from the start time point To of the n−1 th display frame Fn−1 to the first touch reporter time TR1 of the n−1 th display frame Fn−1 is It is different from the second period TI2 from the start time point To of the display frame Fn to the first touch reporter time point TR2 of the n th display frame Fn. The second period TI2 from the start time point To of the nth display frame Fn to the first touch reporter time TR2 of the nth display frame Fn is the n+1th display frame Fn +1) to the first touch reporter time TR3 of the n+1 th display frame Fn+1.

The reason for this is that some touch frames are divided and assigned to two consecutive display frame periods. For example, the third touch frame TF3 is divided and allocated to the n−1 th display frame Fn−1 and the n th display frame Fn, and the fifth touch frame TF5 is allocated to the n−1 th display frame. This is because some touch periods are divided and allocated to two adjacent display frames, such as being allocated to (Fn−1) and the n-th display frame Fn.

A partial period of the third touch frame TF3 is located in the n−1 th display frame Fn−1, and the remaining period of the third touch frame TF3 is located in the n th display frame Fn. At the first touch reporter time point TR2 of the n-th display frame Fn, the first touch reporter for the n-th display frame Fn is generated. The touch reporter includes touch sensing results according to touch driving signals applied during the third touch frame TF3, that is, touch coordinate information. No touch reporter is generated from the nth display frame Fn to the first touch reporter time point TR2.

A partial period of the fifth touch frame TF5 is located in the nth display frame Fn, and the remaining period of the fifth touch frame TF5 is located in the n+1th display frame Fn+1. At the first touch reporter time point TR3 of the n+1 th display frame Fn+1, the first touch reporter for the n+1 th display frame Fn+1 is generated. The touch reporter includes touch sensing results according to touch driving signals applied during the fifth touch frame TF5, that is, touch coordinate information. No touch reporter is generated from the n+1 th display frame Fn+1 to the first touch reporter time point TR3.

In the touch driving device 18 according to the present invention, as shown in FIG. 11 , in the first to ninth display frames, the period from the start of the display frame to the first touch reporter time TR1 to TR9 may be different. In other words, the touch driving device 18 according to the present invention includes the time from the start time To of the first display frame #1 to the first touch reporter time TR1 of the first display frame #1, The time from the start time (To) of the second display frame (#2) to the first touch reporter time (TR2) of the second display frame (#2), the start time (To) of the third display frame (#3) to the first touch reporter time point TR3 of the third display frame #3, and from the start time To of the fourth display frame #4 to the first touch reporter time point TR3 of the fourth display frame #4. Time until the time point TR4, time from the start time To of the fifth display frame #5 to the first touch reporter time TR5 of the fifth display frame #5, time from the sixth display frame # 6) from the start time (To) to the first touch reporter time (TR6) of the sixth display frame (#6), from the start time (To) of the seventh display frame (#7) to the seventh display frame ( Time from the first touch reporter time point TR7 of #7), from the start time To of the eighth display frame #8 to the first touch reporter time TR8 of the eighth display frame #8 Time, the time from the start time point To of the ninth display frame #9 to the first touch reporter time point TR9 of the ninth display frame #9 may be different from each other. On the other hand, according to the present invention, As shown in FIG. 12 , the touch drive device 18 sequentially drives two multiplexers within one touch period in which the touch enable signal TEN is maintained at the second logic level to perform a sensing operation for two touch blocks. may be In the same principle, the touch drive device 18 according to the present invention senses a plurality of touch blocks by sequentially driving a plurality of multiplexers within one touch period in which the touch enable signal TEN is maintained at the second logic level. You can also perform actions.

13 and 14 show another method for increasing the touch reporter rate according to the present invention. 15 to 18 show an example of implementing a frequency hopping technique using the dummy touch section included in FIGS. 13 and 14 .

Referring to FIGS. 13 and 14 , the touch driving device 18 according to the present invention may further allocate at least one dummy touch period DH within one display frame period. The dummy touch period DH may be located between adjacent touch frames.

As shown in FIG. 13 , the dummy touch period DH is between adjacent touch frames within one display frame period, that is, between the first touch frame TF1 and the second touch frame TF2, and between the second touch frame TF2. ) and the third touch frame TF3.

During the dummy touch period DH, the touch driving signal may be applied to at least one or more touch sensor electrodes 22 through one or more touch sensor lines 115 . The touch driving signal may include one or more dummy pulses. The touch driving device 18 may generate a touch sensing value according to the touch driving signal even during the dummy touch period DH. However, the touch driving device 18 may use the touch sensing values generated during the dummy touch period DH for other purposes described later without using them to calculate touch coordinate information.

As shown in FIG. 14 , the dummy touch period DH may be located only between the second touch frame TF2 and the third touch frame TF3 among neighboring touch frames within one display frame period.

This dummy touch period (DH) can be used for frequency hopping technology for noise avoidance as shown in FIGS. 15 to 18, and further used for communication with the active stylus pen 20 as shown in FIGS. 19 and 20. It can be.

One frequency hopping technique of the present invention will be described with reference to FIGS. 15, 16, and 18.

As shown in FIGS. 15 and 16 , the touch driving device 18 according to the present invention counts the low logic period of the touch enable signal TEN to determine the temporal position of the dummy touch period DH ( S1 ). The touch driving device 18 transmits the touch driving signal Tx(f1) having the first driving frequency f1 to some of the touch sensors (eg, touch sensors connected to the first multiplexer) during the dummy touch period DH. is supplied to obtain a first touch sensing value (S2). The touch driver 18 analyzes the noise level of the first touch sensing value and compares the analyzed noise level with a preset reference value (S3). When the analyzed noise level exceeds the reference value, the touch driving device 18 changes the driving frequency of the touch driving signal Tx to a second driving frequency f2 different from the first driving frequency f1, and then performs the second driving. The touch driving signal Tx(f2) having frequency f2 is applied to the next touch frame following the dummy touch period DH (S4). Meanwhile, the touch driving device 18 determines that the analyzed noise level meets the reference value. If not exceeded, the driving frequency of the touch driving signal Tx is maintained at the original first driving frequency f1, and the touch driving signal Tx(f1) having the first driving frequency f1 is connected to the dummy touch period. It is applied to the next touch frame (S5) The touch sensors sensed in the dummy touch period DH may be fixed, may be changed at regular intervals, or may be changed at random time intervals.

Another frequency hopping technique of the present invention will be described with reference to FIGS. 15, 17, and 18.

As shown in FIGS. 15 and 17 , the touch driving device 18 according to the present invention counts the low logic period of the touch enable signal TEN to determine the temporal position of the dummy touch period DH ( S11 ).

The touch driving device 18 according to the present invention transmits the touch driving signal Tx(f1) having the first driving frequency in the first touch frame TF1 prior to the dummy touch period DH to some of the touch sensors (eg, The first touch sensing value obtained by supplying the first touch sensing value to the touch sensors connected to the first multiplexer is stored. The touch driving device 18 according to the present invention transmits the touch driving signal Tx(f2) having a second driving frequency f2 different from the first driving frequency f1 during the dummy touch period DH among the touch sensors. A second touch sensing value is acquired by supplying it to some (for example, touch sensors connected to the first multiplexer) (S12). After analyzing the noise level of the first and second touch sensing values, the touch driving device 18 according to the present invention compares the noise level of the first touch sensing value with the noise level of the second touch sensing value. (S13). The touch driving device 18 according to the present invention applies a driving frequency having a smaller noise level among the first and second driving frequencies f1 and f2 to the second touch frame TF2 following the dummy touch period DH. (S14). The touch sensors sensed in the dummy touch period DH may be fixed, may change at regular intervals, or may change at random time intervals.

FIG. 19 shows an example of a touch driving signal Tx for communication with the active stylus pen 20 of FIG. 2 . And, FIG. 20 shows an example of sensing pen information based on the pen driving signal (S-Tx) input from the active stylus pen 20 of FIG. 2 .

The active stylus pen 20 is a device that generates a pen driving signal (S-Tx) based on a touch driving signal (Tx) input from a touch screen (TSP) and then outputs the pen driving signal (S-Tx) to a contact point with the touch screen (TSP). . The touch driving device 18 can effectively detect the touch position of the active stylus pen 20 by sensing the pen driving signal S-Tx. Recently, the active stylus pen 20 requires various additional functions such as touch pressure (pen pressure) information, touch ID information, and driving information related to various touch buttons. Accordingly, the active stylus pen 20 can detect a dummy touch section according to a dummy pulse different from the touch driving signal Tx as shown in FIG. 19 and distinguish a touch frame accordingly. In addition, the active stylus pen 20 may process the pen driving signal S-Tx in units of touch frames to output the pen driving signal S-Tx including the above additional functions.

The touch driving device 18 transmits the touch driving signal Tx to the display panel (or touch screen) in the touch section (the section where M01, M02, M03, MO4, ..., M14 operate) within the touch frame TF. and output a dummy pulse different from the touch driving signal Tx to the display panel in the dummy touch period DH. The dummy pulse may be generated differently from the touch driving signal Tx through various methods. For example, the number of dummy pulses may be different from that of the touch driving signal Tx, as shown in FIG. 19 . In other words, while the touch driving signal Tx generated in one touch period is composed of 7 pulses including 3 sub pulses and 4 main pulses, the dummy pulse may be composed of 2 pulses. Here, the sub-pulse of the touch driving signal Tx is an additional pulse used to check the validity of the touch driving signal Tx. Meanwhile, the dummy pulse may have a different pulse width or a different pulse amplitude compared to the touch driving signal Tx.

The active stylus pen 20 can distinguish the touch frame TF by detecting that the dummy pulse input from the display panel is different from the sub-pulse of the touch driving signal Tx. The active stylus pen 20 generates a pen driving signal (S-Tx) synchronized with the main pulse of the touch driving signal (Tx) and outputs the pen driving signal (S-Tx) to the display panel, including the pulse amplitude and pulse width of the pen driving signal (S-Tx). , and the number of pulses is controlled in units of J (J is a natural number) touch frame to express binary numbers “0” and “1”, thereby realizing the various additional functions through the pen driving signal (S-Tx). . For example, as shown in FIG. 20, the active stylus pen 20 controls the pulse amplitudes (A1, A2) (A1<A2) of the pen driving signal (S-Tx) in units of one touch frame to transmit pen information with one touch. 1 bit can be allocated per frame. In this case, in order to implement 8-bit pen information, the active stylus pen 20 may utilize 8 touch frames. Meanwhile, when additional functions are expressed using the pen driving signal S-Tx, the pen driving signal S-Tx should not be processed to such an extent that the touch position cannot be detected. In other words, both of the two different pulse amplitudes to represent the binary number must satisfy the minimum size required for detecting the touch position, and both the two pulse widths to represent the binary number must satisfy the minimum size required for detecting the touch position. Similarly, the two pulse numbers to represent the binary number must satisfy the minimum size required for detecting the touch position.

Touch raw data may increase in proportion to the pulse amplitude, pulse width, and number of pulses of the pen driving signal S-Tx. The touch driver 18 detects the amount of change in touch raw data according to the pen drive signal S-Tx, and detects not only the touch input position but also pen information related to additional functions according to the amount of change. can As described above, the present invention increases the touch reporter rate by a non-integer multiple (N.M times, N and M are positive integers) compared to the display frame rate, thereby reducing the surplus period not utilized as a touch period within one display frame period. can be eliminated and the touch reporter rate can be further improved.

Furthermore, the present invention further allocates a dummy touch section for distinguishing touch frames within one display frame period and utilizes the dummy touch section for communication with an active stylus pen, thereby effectively providing not only a touch input position but also pen additional functions. can detect

Through the above description, those skilled in the art will understand that various changes and modifications are possible without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be determined by the claims.

10: touch-sensitive display device DIS: display panel
12: data driving circuit 14: gate driving circuit
16: timing controller 18: touch drive device
19: host system 20: active stylus pen

Claims (24)

A plurality of pixels and a plurality of touch sensors are provided, each touch sensor is connected to at least one or more pixels, and driven through a plurality of consecutive display frame periods, and in each display frame period, one frame of image data is a display panel applied to pixels; and
A touch driving device for applying touch driving signals to the touch sensors during one touch frame;
The one touch frame starts in a first display frame period among the display frame periods and ends in a second display frame period immediately following the first display frame period among the display frame periods;
The touch drive device,
Prior to a dummy touch period of the first display frame period, a touch driving signal having a first driving frequency is applied to at least one or more touch sensors during the touch frame to obtain a first touch sensing value for generating a touch reporter;
During the dummy touch period of the first display frame period, a touch driving signal having a second driving frequency different from the first driving frequency is applied to the at least one or more touch sensors to generate a second touch irrelevant to the generation of the touch reporter. obtain a sensed value,
comparing a noise level for the first touch sensing value with a noise level for the second touch sensing value;
and selecting a driving frequency having a smaller noise level among the first and second driving frequencies as the driving frequency of the touch driving signal according to the comparison result. According to claim 1,
The touch driving device applies touch driving signals to the touch sensors,
Applying the touch driving signals to first touch sensors among the touch sensors during the first display frame period;
Applying the touch driving signals to second touch sensors among the touch sensors during the second display frame period;
Touch coordinate information obtained based on the touch driving signals applied to the first touch sensors during the first display frame period and the touch driving signals applied to the second touch sensors during the second display frame period A touch-sensitive display device that generates a touch reporter including a. According to claim 1,
The touch drive device,
A first touch reporter is generated in the first display frame period, and no touch reporter is generated between a start time of the first display frame period and a time when the first touch reporter is generated;
A second touch reporter is generated in the second display frame period, the second touch reporter is generated based on touch driving signals applied to the touch sensors during the one touch frame, and in the second display frame period A touch-sensitive display device in which no touch reporter is generated between a starting point and a point in time when the second touch reporter is generated. According to claim 1,
The touch reporter rate of the touch drive device is higher than the display frame rate of the display device by a non-integer multiple. According to claim 1,
The touch drive device,
further allocating at least one dummy touch period in each display frame period;
The dummy touch period is located between adjacent touch frames. delete delete According to claim 5,
The touch drive device,
outputting touch drive pulses and dummy pulses to at least one or more touch sensors and receiving a pen drive signal output from a stylus pen;
the touch driving pulses are included in the touch driving signals, the dummy pulses have characteristics different from those of the touch driving pulses, and are output to the dummy touch period;
The stylus pen distinguishes touch frames based on the dummy pulses and outputs the pen driving signal synchronized with the touch driving pulses to the at least one touch sensor. In a driving circuit of a touch-sensitive display device having a display panel including a plurality of pixels and a plurality of touch sensors, each touch sensor connected to at least one pixel,
a data driving circuit for driving the display panel in a plurality of consecutive display frame periods and applying one frame of image data to the pixels in each display frame period; and
A touch driving device for applying touch driving signals to the touch sensors during one touch frame;
The one touch frame starts in a first display frame period among the display frame periods and ends in a second display frame period immediately following the first display frame period among the display frame periods;
The touch drive device,
Prior to a dummy touch period of the first display frame period, a touch driving signal having a first driving frequency is applied to at least one or more touch sensors during the touch frame to obtain a first touch sensing value for generating a touch reporter;
During the dummy touch period of the first display frame period, a touch driving signal having a second driving frequency different from the first driving frequency is applied to the at least one or more touch sensors to generate a second touch irrelevant to the generation of the touch reporter. obtain a sensed value,
comparing a noise level for the first touch sensing value with a noise level for the second touch sensing value;
A driving circuit of a touch-sensitive display device that selects a driving frequency having a smaller noise level among the first and second driving frequencies as a driving frequency of a touch driving signal according to a result of the comparison. According to claim 9,
The touch driving device applies touch driving signals to the touch sensors,
Applying the touch driving signals to first touch sensors among the touch sensors during the first display frame period;
Applying the touch driving signals to second touch sensors among the touch sensors during the second display frame period;
Touch coordinate information obtained based on the touch driving signals applied to the first touch sensors during the first display frame period and the touch driving signals applied to the second touch sensors during the second display frame period A driving circuit of a touch-sensitive display device generating a touch reporter including a. According to claim 9,
The touch drive device,
A first touch reporter is generated in the first display frame period, and no touch reporter is generated between a start time of the first display frame period and a time when the first touch reporter is generated;
A second touch reporter is generated in the second display frame period, the second touch reporter is generated based on touch driving signals applied to the touch sensors during the one touch frame, and in the second display frame period A driving circuit of a touch-sensitive display device in which no touch reporter is generated between a starting point and a point in time when the second touch reporter is generated. According to claim 9,
The touch reporter rate of the touch drive device is higher than the display frame rate of the display device by a non-integer multiple. According to claim 9,
The touch drive device,
further allocating at least one dummy touch period in each display frame period;
The dummy touch period is a driving circuit of a touch-sensitive display device positioned between adjacent touch frames. delete delete According to claim 13,
The touch drive device,
outputting touch drive pulses and dummy pulses to at least one or more touch sensors and receiving a pen drive signal output from a stylus pen;
the touch driving pulses are included in the touch driving signals, the dummy pulses have characteristics different from those of the touch driving pulses, and are output to the dummy touch period;
The stylus pen distinguishes touch frames based on the dummy pulses and outputs the pen driving signal synchronized with the touch driving pulses to the at least one touch sensor. A method of driving a touch-sensitive display device having a display panel including a plurality of pixels and a plurality of touch sensors, each touch sensor connected to at least one pixel, comprising:
driving the display panel in a plurality of consecutive display frame periods and applying one frame of image data to the pixels in each display frame period; and
Applying touch driving signals to the touch sensors during one touch frame;
The one touch frame starts in a first display frame period among the display frame periods and ends in a second display frame period immediately following the first display frame period among the display frame periods;
Applying touch driving signals to the touch sensors during one touch frame includes:
obtaining a first touch sensing value for generating a touch report by applying a touch driving signal having a first driving frequency to one or more touch sensors during the touch frame prior to a dummy touch period of the first display frame period;
During the dummy touch period of the first display frame period, a touch driving signal having a second driving frequency different from the first driving frequency is applied to the at least one or more touch sensors to perform second touch sensing regardless of generation of a touch reporter. obtaining a value;
comparing a noise level for the first touch sensing value with a noise level for the second touch sensing value; and
and selecting a driving frequency having a smaller noise level among the first and second driving frequencies as a driving frequency of a touch driving signal according to a result of the comparison. 18. The method of claim 17,
Applying touch driving signals to the touch sensors during the one touch frame includes:
Applying the touch driving signals to first touch sensors among the touch sensors during the first display frame period;
Applying the touch driving signals to second touch sensors among the touch sensors during the second display frame period;
Touch coordinate information obtained based on the touch driving signals applied to the first touch sensors during the first display frame period and the touch driving signals applied to the second touch sensors during the second display frame period A method of driving a touch-sensitive display device that generates a touch reporter including a. 18. The method of claim 17,
Applying touch driving signals to the touch sensors during the one touch frame includes:
A first touch reporter is generated in the first display frame period, and no touch reporter is generated between a start time of the first display frame period and a time when the first touch reporter is generated;
A second touch reporter is generated in the second display frame period, the second touch reporter is generated based on touch driving signals applied to the touch sensors during the one touch frame, and in the second display frame period A method of driving a touch-sensitive display device in which no touch reporter is generated between a starting point and a point in time when the second touch reporter is generated. 18. The method of claim 17,
A method of driving a touch-sensitive display device in which a touch reporter rate is higher than a display frame rate of the display device by a non-integer multiple. 18. The method of claim 17,
At least one dummy touch period is further allocated in each display frame period;
The dummy touch period is located between adjacent touch frames. delete delete According to claim 21,
outputting touch drive pulses and dummy pulses to one or more touch sensors; and
Further comprising receiving a pen drive signal output from the stylus pen,
the touch driving pulses are included in the touch driving signals, the dummy pulses have characteristics different from those of the touch driving pulses, and are output to the dummy touch period;
The stylus pen distinguishes touch frames based on the dummy pulses, and outputs the pen driving signal synchronized with the touch driving pulses to the at least one or more touch sensors.

Images